It is known that such depollution means may comprise, for example, a NOx trap which is a system for reducing the polluting emissions of the heat engines of motor vehicles.
The engine is then associated with means for controlling its operation in order to switch it between standard operation in lean mode and regeneration operation in rich mode, in accordance with various parameters for controlling the operation of the engine.
In the standard operating mode in lean mode, the NOx trap stores the nitrogen oxides and, when the trap is saturated, its regeneration is triggered by switching the engine to rich operating mode, for the purpose of removing the NOx from the store, in which mode the engine produces reducing agents, such as, for example, CO and HC.
This is conventionally effected by modifying at least one parameter for controlling engine operation, that is to say, at least one parameter relating to the injection of fuel into the engine (quantity, phasing, pressure, etc. . . . ) and/or at least one parameter of the engine air supply loop (air flow rate, recycling, pressure of the turbocompressor, etc. . . . ).
The various adjustments to those parameters enable predetermined performance objectives in terms of torque, pollutant emissions, noise, etc. . . . to be achieved.
However, the calibration of the engine in rich operating mode is effected on the workbench under standard environmental conditions.
The object of the invention is to improve such a system in order to take into account variations in the environmental conditions.